Undefined index in portfolio.php

Question

It seems like every hour I have another question I can't seem to figure out with pset7 :( I'm sorry to whoever is kindly answering all of these queries and I appreciate the help a lot! I know at least one other person who has had a similar undefined index problem, too, and am wondering if something might be causing it that I just don't have the knowledge base to figure out.

I am trying to get portfolio.php to work but for some reason my queries don't seem to be working. Right now I have:

$row = query("SELECT symbol, shares FROM Portfolio WHERE id=?", $_SESSION["id"]); 
$cash = query("SELECT cash FROM users WHERE id=11", $_SESSION["id"]); 

I keep being told cash is an undefined index and when I try to print it out as a test it doens't work. furthermore, when I pass the values as $positions to portfolio.php (a template) with this code:

render("portfolio.php", ["title" => "Portfolio", "positions"=>"$positions", "cash"=>"$cash"]);

And then I do foreach ($position as $positions)

I get told position is an undefined variable. So even though that one seems to exist in index.php it doesn't work in portfolio.php, while cash works in neither. I re-watched the videos many times but can't seem to find a typo in the code above. I have tried putting the variables in render in and out of quotes (just because I had to try something) but it made no difference.

Answer 1

I myself have not yet used the query function, but based on description of this problem set, it returns an array of rows, not a single one. So I would say your best bet is to go with something like this:

$cash = query("SELECT cash FROM users WHERE id=11", $_SESSION["id"]);
$cash = $cash[0]['cash'];

Hope this solves your first problem. Feel free to ask if something isn't clear.

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EDIT - there is actually an example for this on the pset7 page:

$rows = query("SELECT LAST_INSERT_ID() AS id");
$id = $rows[0]["id"];

Based on this, the returned value really is just an array of rows which you can take the first (0) element of.

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As for the positions one, I need you to show me the output of var_dump($positions) so I can assist you further.